Should I lie about my baby on the ferry booking?

[yesway]

I am about to book a rail and sail ticket for us to have a weekend away in December. We are booking an overnight ferry and can book a 5 berth cabin which looks perfect. It has a double bed with a single bunk above and then two normal bunks. However, we are a family of 6. I think we would fit comfortably into the 5 berth cabin with baby in bed with us (he will be 5 months old). The web site won't let me book the ticket though because we are too many.

As far as I can see I can either:

Book a cabin of 5 and not include baby on the ticket and hope no-one queries it.

Book two cabins and have to pay more and split the family up and not be able to babysit for each other while we go and get a meal.....

What would you do?

Ring them up and see what they say. A lot of times we haven't been able to book through websites but have been told there are free baby cots. (Not on the ferry though.)

Thanks for that. You are very sensible and people are so much better to deal with than computers. We're booked.